The present invention relates to a resist stripping agent for use in fabricating circuits or forming electrodes on semiconductor devices for semiconductor integrated circuits or liquid crystal displays, and further to a process of producing semiconductor devices using the resist stripping agent.
Semiconductor devices for semiconductor integrated circuits or liquid crystal displays have been generally produced by the steps of coating an inorganic substrate with a resist composition; patterning the resist film by exposure to light and subsequent development; etching exposed portions of the inorganic substrate using the patterned resist film as a mask to form minute circuits; and removing the resist film from the inorganic substrate. Alternatively, after forming minute circuits, the resist film is ashed and the remaining resist residues are removed from the inorganic substrate.
Japanese Patent Application Laid-Open Nos. 62-49355, 62-95531 and 5-273768 disclose to remove the resist film and resist residues by organic amine-containing stripping agents free of water. However, the proposed organic amine-containing stripping agents have poor removal capability to the resist film after etching and the resist residue after etching and ashing.
Fine processing recently coming to be extensively employed in manufacturing semiconductor devices requires more strictly controlled etching conditions, this in turn requiring resist films to have surfaces with higher hardness. Also, the fine processing creates resist residues having complicated chemical compositions by etching and plasma ashing. The proposed organic amine-containing stripping agents have been found to be less effective for removing such resist films and resist residues.
In case of dry etching, sidewall polymers as resist residues are formed from dry etching gas, resist materials and various inorganic materials. The known organic amine-containing stripping agents are also less effective for removing the sidewall polymers.
Japanese Patent Application Laid-Open Nos. 64-81949, 64-81950 and 6-266119 disclose alkanol amine-containing aqueous stripping agents. However, these alkanol amine-containing aqueous stripping agents are still insufficient for removing the above resist films and resist residues.
The substrates of semiconductor devices for semiconductor integrated circuits or liquid crystal displays are recently made of various inorganic materials. Therefore, a resist stripping agent resistant to corrosion of such inorganic materials have been demanded to be developed.
A general object of the present invention is to solve the above problems in the prior art stripping agents.
Another object of the present invention to provide a resist stripping agent which easily removes resist films coated on an inorganic substrate at low temperatures in a short period of time without corroding the inorganic substrates made of various inorganic materials, thereby ensuring fabrication of high precision circuits.
A yet another object of the present invention is to provide a resist stripping agent which easily removes resist films remaining after etching on an inorganic substrate at low temperatures in a short period of time without corroding the inorganic substrates made of various inorganic materials, thereby ensuring fabrication of high precision circuits.
A still another object of the present invention is to provide a resist stripping agent which easily removes resist residues remaining after ashing subsequent to etching on an inorganic substrate at low temperatures in a short period of time without corroding the inorganic substrates made of various inorganic materials, thereby ensuring fabrication of high precision circuits.
A further object of the present invention is to provide a process of producing semiconductor devices using such resist stripping agents.
As a result of extensive researches in view of the above objects, the inventors have found that a resist stripping agent comprising a specific alkanolamine (stripping alkanolamine) removes patterned resist films and resist residues remaining after etching and resist residues remaining after ashing subsequent to etching easily and quickly without corroding circuit elements, insulating films, etc., thereby ensuring fine processing to produce high precision circuits. The present invention has been accomplished based on this finding.
Thus, the present invention provides:
(A) a resist stripping agent comprising a stripping alkanolamine having in its molecule at least one functional group represented by the following formula (I): 
wherein R1 and R2 are each hydrogen atom, C1-C8 alkyl or C1-C8 alkenyl;
(B) a process of producing semiconductor devices including a step of removing resist films and/or resist residues remaining after etching resist films by the resist stripping agent; and
(C) a process of producing semiconductor devices including a step of removing resist films and/or resist residues remaining after ashing etched resist film by the resist stripping agent.